GB2322310A

GB2322310A - Shredder

Info

Publication number: GB2322310A
Application number: GB9803767A
Authority: GB
Inventors: Alan Rodney Pickard
Original assignee: POWERTECH IND Ltd
Current assignee: POWERTECH IND Ltd
Priority date: 1997-02-25
Filing date: 1998-02-24
Publication date: 1998-08-26
Anticipated expiration: 2018-02-24
Also published as: GB2322310B; GB9703911D0; GB9803767D0

Abstract

A shredding ring (1) for incorporation in a shredding machine comprises an annular core (2) adapted to be secured in a drivable manner on a rotary drive shaft; a plurality of angularly spaced-apart radial abutment members (8) projecting from the arcuately convex outer periphery (5) of the core (2) with adjacent surfaces of adjacent abutment members defining abutment gaps (9); a plurality of arcuate segments (11), together extending over 360‹, each provided with an inner arcuately concave seating surface (12) for engagement with a portion of the complementary convex outer periphery (5) of the core, and each provided with a recess (13) of profile complementary to that of an abutment member whereby the segment (11) may be fitted to the core (2) by engagement of its recess (13) over an abutment member; a shoulder (15) provided at each end of each arcuate segment (11); at least one of the arcuate segments being adapted to carry a wear blade (28); a plurality of clamping blocks (18) having clamping surfaces (16) adapted to engage adjacent shoulders (15) of two adjacent segments (11); means (21, 22, 10) to releasebly secure the clamping blocks (18) to the core (2); and means (25, 26, 27) to releasably secure the or each wear blade (28) to its segment (11). The invention also includes a shredding machine provided with such a ring(s).

Description

TITLE OF THE INVENTION: Shredder FIELD OF THE INVENTION This invention relates to a shredding ring, and to a shredding machine incorporating at least one such ring, being a machine through which a material such as domestic refuse is fed to achieve a uniform sizing for subsequent landfill or incineration.

BACKGROUND OF THE INVENTION A shredding machine conventionally comprises a drive shaft, usually rotatable at relatively relatively low speed, about a horizontal axis, on which the shredding ring(s) is mounted, the shredding ring normally incorporating at least one projecting blade adapted to cooperate with either a static anvil or a second shredding ring on a second shaft, to define a gap or nip of dimensions approximating to the product size required to exit from the shredding machine. Apart from shredding domestic refuse, such a shredding machine could also be employed for the shredding or chopping of waste or scrap industrial items such as cables, or for the sizing of minerals such as coal, limestone etc., as part of mining or quarrying operations.

Known shredding rings are basically annular, carrying at least one and usually two or more peripheral blades. Clearly, from time to time, blade replacement is unavoidable due to wear and/or damage, particularly in the case of sizing domestic waste where the content of the waste is to some extent unknown. However, known system blade replacement usually involves ring replacement, typically every three months at substantial costs (e.g. < 20,000 per annum) and the removal and replacement of a ring is a relatively time consuming operation, with a consequent inability to handle waste during the ensuing down time.

OBJECT OF THE INVENTION A basic object of the present invention is to provide a shredding ring, and a shredding machine incorporating at least one such ring, wherein blade replacement is a simple, mechanical task, involving minimal down time.

SUMMARY OF THE INVENTION According to a first aspect of the present invention, there is provided a shredding ring for incorporation in a shredding machine comprising : (1) an annular core adapted to be secured in a drivable manner on a rotary drive shaft; (2) a plurality of angularly spaced-apart radial abutment members projecting from the arcuately convex outer periphery of the core with adjacent surfaces of adjacent abutment members defining abutment gaps; (3) a plurality of arcuate segments, together extending over 3600, each provided with an inner arcuately concave seating surface for engagement with a portion of the complementary convex outer periphery of the core, and each provided with a recess of profile complementary to that of an abutment member whereby the segment may be fitted to the core by engagement of its recess over an abutment member; (4) a shoulder provided at each end of each arcuate segment; (5) at least one of the arcuate segments being adapted to carry a wear blade; (6) a plurality of clamping blocks having clamping surfaces adapted to engage adjacent shoulders of two adjacent segments; (7) means to releasably secure the clamping blocks to the core; and (8) means to releasably secure the or each wear blade to its segment.

According to a second aspect of the present invention, there is provided a shredding machine incorporating at least one shredding ring as defined above.

Thus, in detail, the core may be secured in a drivable manner on the drive shaft by providing the central aperture with a pair of 1800 opposed flats, to define two, planar drive surfaces, for seating and driving engagement with a pair of complementary flats on the drive shaft and additionally may be provided with twelve abutment members, or teeth, located at 300 intervals, with location gaps defined between adjacent teeth, whilst the segments may be six in number, thereby each extending over a 600 arc. Thus, with a six segment arrangement, all segments may be identical, if six wear blades are required. If fewer thank six wear blades are required, then the segments will be a mix of two types, what may be termed wear blade segments, and in-fill segments. The means to secure each clamping block to the core may comprise a bolt adapted to screw into a tapped radial hole provided in the core at the bottom of each location gap, the bolt preferably having an enlarged head and a recessed hexagon socket engageable by an Allen key. The or each segment intended to carry a wear blade is preferably provided with a projecting beak or nose to which the wear blade is attached, preferably by a nut and bolt, the latter preferably having a similar sized hexagon socket whereby the same Allen key may be employed.

The segments and the clamping blocks are preferably positively locatable on the external periphery of the annular core, by providing each segment and block with a radial tooth, projecting from its arcuately concave surface, the tooth having a profile, which is preferably slightly tapered, complementary to that of an abutment gap, so that drive forces are imparted by flanks of the projecting abutment members of the core, to the teeth of the segments and blocks.

Preferably, the segments are provided with parallel, spaced-apart lateral flanges to deter entry of particles of the material being shredded or chopped into the zone of the abutment members of the core.

The wear blade may have a tongue and groove interfit, for mechanical location, between a rear face of the blade and a forward face (in the direction of rotation) of the beak or nose of the associated segment, such interfit resisting lateral displacement of a wear plate with respect to its beak or nose, in use.

The wear blade, if in the form of a generally flat plate of wear resistant steel, produces a shearing effect on the material to be shredded or chopped up. If the shredding of a particular material could benefit from a bursting effect, the wear plate and/or its nose, may be provided with a pick, preferably with a tungsten carbide insert, of a general kind used in mining, or in road planing, to provide, as the rotor rotates, a bursting effect followed by a shearing effect.

It follows that with the embodiment of core capable of receiving six segments, the user may choose to employ one wear blade segment and five in-fill segments, or two wear blade segments located 1800 apart with four in-fill segments; or, as indicated previously, six wear blade segments. Furthermore, two or more shredding rings in accordance with the first aspect of the invention may be mounted on a common shaft with the wear blade segments staggered, to give a scroll effect.

It follows that, with the ability to detach a segment - whether a wear blade segment or an in-fill segment - within a matter of a minute or so simply by unscrewing its securing bolt, not only can a worn or damaged blade or segment be changed at insignificant cost (e.g., < 100) with minimal and inconsequential downtime, but the pattern and/or number of segments with wear blades may be readily adjusted to a better suited configuration should it be found that the originally selected configuration of wear blades is not producing optimum results.

SUMMARY OF THE DRAWINGS One embodiment of shredding ring, and its components, in accordance with the first aspect of the invention is shown in the accompanying drawings, in which: Figure 1 is a side elevation of a shredding ring in accordance with the first aspect of the invention; Figure 2 corresponds to figure 1 but shows certain elements removed; Figure 3 is a section on the line III-III of figure 2; Figure 4 is a side elevation of an arcuate segment with a wear blade; Figures 5, 6 and 7 are, respectively, a front elevation, a rear elevation, and a plan view of figure 4; Figures 8 and 9 are, respectively, a side elevation and an end elevation of a first embodiment of arcuate segment without a wear blade; Figures 10 and 11 are, respectively, a side elevation and an end elevation of a second embodiment of arcuate segment without a wear blade; Figures 12 and 13 are, respectively, a side elevation and a sectional view of a clamping block; Figures 14 and 15 are, respectively, a side elevation and a front elevation of a plug; and Figures 16, 17 and 18 are, respectively, a side elevation, a front elevation and a plan view of a pick tip to be fitted to the pick body of figures 4 to 7.

DETAILED DESCRIPTION OF THE DRAWINGS In all figures, like components are accorded like reference numerals.

A shredding ring 1 for incorporation in a shredding machine (not shown) comprises an annular core 2 adapted to be secured in a driveable manner on a rotary drive shaft, by providing the central aperture 3 of the core 2 with a pair of 1800 opposed flats 4, to define two, planar drive surfaces, for seating and driving engagement with a pair of complementary flats of the drive shaft of the shredding machine. The core 2 has an arcuately convex outer periphery 5 comprising a pair of lateral seating shoulders 6 and a central rib 7, from which rib 7 project radially twelve abutment members or teeth 8, located at 300 spacing, with location gaps 9 defined between adjacent teeth. From a base of each gap 9, extends a blind, tapped hole 10 into the core 2.

As indicated in Figure 1, six arcuate segments 11, each extending over a 60 arc and thereby together extending over 360 , are each provided with a pair of spaced-apart inner, arcuately concave seating surfaces 12 for engagement with a portion of the shoulders 6.

Furthermore, each segment 11 is provided with a recess 13 of profile complementary to that of a tooth 8, whereby each segment 11 may be fitted to the core 2 by engagement of its recess 13 over a selected tooth 8. Furthermore, each arcuate segment 11 is provided with leading and trailing pairs of spaced-apart flanges 14-firstly to embrace a portion of an adjacent leading and an adjacent trailing tooth 8 and secondly providing clamping surfaces 15 for engagement by clamping surfaces 16 of an enlarged head 17 of a clamping block 18 provided with a location spigot 19 to fit between other portions of the spaced-apart flanges 14 of two adjacent segments 11. To achieve clamping, each clamping block 18 is provided with a through hole 20 to receive a clamping bolt 21 engageable in a tapped hole 10. Head 22 of the bolt is recessed for engagement by an Allen Key, whilst each block 18 is countersunk to accommodate the bolt head 22.

As indicated in Figure 1, four of the arcuate segments 11 are identical, while the remaining two, which are located 1800 apart are each provided with a beak or nose 23 having a through hole 24 for passage of the stem 25 of a clamping bolt 26 with a nut 27 whereby a releasable wear blade 28 (detailed in Figures 16 to 18) also having a through hole 29 and being countersunk at 30 may be secured to the leading end of the nose 23. The head of the bolt 26 is recessed for insertion of an Allen Key. The wear blade 28 is provided with a tongue 31 to fit a groove 32 provided in the leading face of the nose 23 for mechanical location of the wear blade 28.

Figures 14 and 15 show a plug 33 eg of synthetic plastics material, having a hexagonal recess 34 for housing the nut 27, which plug may be fitted to the trailing end of each nose 23 to be retained by a roll pin passing through aligned holes 35 in the nose 23 and hole 36 in the plug 31.

Claims

1. A shredding ring for incorporation in a shredding machine comprising : (1) an annular core adapted to be secured in a drivable manner on a rotary drive shaft; (2) a plurality of angularly spaced-apart radial abutment members projecting from the arcuately convex outer periphery of the core with adjacent surfaces of adjacent abutment members defining abutment gaps; (3) a plurality of arcuate segments, together extending over 360 , each provided with an inner arcuately concave seating surface for engagement with a portion of the complementary convex outer periphery of the core, and each provided with a recess of profile complementary to that of an abutment member whereby the segment may be fitted to the core by engagement of its recess over an abutment member; (4) a shoulder provided at each end of each arcuate segment; (5) at least one of the arcuate segments being adapted to carry a wear blade; (6) a plurality of clamping blocks having clamping surfaces adapted to engage adjacent shoulders of two adjacent segments; (7) means to releasably secure the clamping blocks to the core; and (8) means to releasably secure the or each wear blade to its segment.

2. A shredding ring as claimed in Claim 1, wherein the core is securable on the drive shaft by providing the central aperture with a pair of 1800 opposed flats, to define two, planar drive surfaces, for seating and driving engagement with a pair of complementary flats on the drive shaft.

3. A shredding ring as claimed in Claim 1 or Claim 2, wherein the core is provided with twelve abutment members, or teeth, located at 300 intervals, with location gaps defined between adjacent teeth.

4. A shredding ring as claimed in Claim 3, wherein six segments are provided, each extending over a 60O arc.

5. A shredding ring as claimed in Claim 4, wherein the six segments are identical, and six wear blades are provided.

6. A shredding ring as claimed in Claim 3, wherein six segments are a mix of two types, what may be termed wear blade segments, and in-fill segments.

7. A shredding ring as claimed in any preceding claim, wherein the means to secure each clamping block to the core is a bolt adapted to screw into a tapped radial hole provided in the core at the bottom of each location gap.

8. A shredding ring as claimed in Claim 7, wherein the bolt has an enlarged head and a recessed hexagon socket engageable by an Allen key.

9. A shredding ring as claimed in any preceding claim, wherein the or each segment intended to carry a wear blade is provided with a projecting beak or nose to which the wear blade is attached.

10. A shredding ring as claimed in Claim 9, wherein attachment of the wear blade to the beak or hose is by a nut and bolt.

11. A shredding ring as claimed in Claim 10, wherein the bolt also has a hexagon socket.

12. A shredding ring as claimed in any preceding claim, wherein the segments and the clamping blocks are positively locatable on the external periphery of the annular core, by providing each segment and block with a radial tooth projecting from its arcuately concave surface, the tooth having a profile complementary to that of an abutment gap.

13. A shredding ring as claimed in Claim 12, wherein the tooth profile is slightly tapered.

14. A shredding ring as claimed in any preceding claim, wherein the segments are provided with parallel, spaced-apart lateral flanges.

15. A shredding ring as claimed in Claim 9, and any claim appendant thereto, wherein the wear blade has a tongue and groove interfit, for mechanical location, between a rear face of the blade and a forward face (in the direction of rotation) of the beak or nose of the associated segment.

16. A shredding ring as claimed in any preceding claim, wherein the wear blade is in the form of a generally flat plate of wear resistant steel.

17. A shredding ring as claimed in any one of Claims 1 to 15, wherein the wear plate, and/or any beak or nose thereof, is provided with a pick.

18. A shredding ring as claimed in Claim 17, wherein the pick has a tungsten carbide insert.

19. A shredding ring as claimed in any preceding claim, having a core capable of receiving six segments, comprising one wear blade segment and five in-fill segments.

20. A shredding ring as claimed in any preceding claim, having a core capable of receiving six segments, comprising two wear blade segments located 1800 apart with four in-fill segments.

21. A shredding ring as claimed in any preceding claim, having a core capable of receiving six segments, comprising six wear blade segments.

22. A shredding ring substantially as herein before described with reference to the accompanying drawing(s).

23. A shredding machine incorporating at least one shredding ring as defined in any preceding claim.

24. A shredding machine comprising two or more shredding rings in accordance with any of Claims 1 to 22, mounted on a common shaft with the wear blade segments staggered, to give a scroll effect.